1. Field of the Invention
The field of the invention relates to arc welding apparatus, and particularly to shields for such apparatus.
2. Brief Description of the Prior Art
Mig and tig welders are in widespread use today. Mig welders are commonly employed for joining metal plates or panels which are substantially the same in thickness. Such materials may be tack welded, stitch welded or otherwise joined.
A mig welder typically includes a handle, a torch tip connected to the handle, a mig wire extending from the torch tip, and a gas nozzle threadably connected to the torch tip. The torch tip includes an external thread coupled to an internal thread within the gas nozzle. When the gas nozzle is attached to the torch tip, the mig wire extends slightly beyond the open end of the gas nozzle. The handle includes a trigger for controlling the operation of the apparatus.
A tig welder may be used for joining metal pieces having different thicknesses, and may also be used where greater precision is required than can be achieved through the use of a mig welder. A rig welder includes a handle, tip assembly coupled to the handle, and a solid rod extending from the tip assembly through the nozzle. The rod may be advanced as necessary. The handle typically does not include a trigger. A foot pedal is instead generally employed for controlling the flow of gas and the amperage.
Persons employing either of the above types of welders must take precautions in order to avoid injury due to harmful welding flash. The light generated at the tip of the nozzle is intense, and is capable of damaging the eyes and skin. In order to protect against such injuries, a person ordinarily wears a welding helmet which includes a translucent shield. The shield provides limited visibility when the welder is operated. It is usually impossible to view the workpieces, however, prior to generation of the arc plasma at the nozzle. The shield must accordingly be flipped up prior to beginning the welding process, the nozzle placed at the site of the weld, the shield flipped down, and the joint finally welded. As the workpieces often need to be welded at a plurality of points or along a plurality of lines, the constant need to manipulate the shield becomes tedious and time-consuming. In addition, the position of the nozzle may be inadvertently changed while the shield is flipped, resulting in an inaccurate weld. The weld site is often difficult to locate, making use of a helmet almost totally impractical. As discussed above, the health risks to a person who operates without a shield are substantial.
Another approach for protecting against welding flash has been to use a hand-held shield. While such shields are easier to manipulate than the shield on a helmet, they are impractical for any job which requires the use of two hands. Like the shield mounted to helmets, no protection is provided to persons other than the one who is actually welding. As many workplaces do not include isolated areas for welding, all persons in the workplace may be at risk.